Power-operated hydraulic actuator



Nov. 11, 1952 .E. J. RINGER POWEROPERATED HYDRAULIC ACTUATOR Filed Dec.22, 1945 MW. we a w V Nova 11, 1952 J, RINGER 2,617,261

POWER-OPERATED HYDRAULIC ACTUATOR Filed Dec. 22, 1945 2 SHEETSSHEET 2awe/14M 6106 d. PIA/65A.

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@afented Nov. 11, 1952 UNITED STATES PATENT @E'FICE POWER-OPERATEDHYDRAULIC ACTUATOR Application December 22, 1945, Serial No. 636,582

(01. Gil-54.6)

9 Claims.

This invention relates to power operated hydraulic actuators andparticularly to the construction of a combined difierential air pressurepower unit and hydraulic cylinder operated thereby, such as disclosed inPrice Patent No. 2,353,755, which issued July 18, 19%. Reference is alsomade to my co-pending divisional application Serial No. 293,795, filedJune 16, 1952. l

The primary object of the present invention is to improve and simplifythe construction of such a combination power unit and hydraulicactuator, to the end of reducing the expense of building the same,particularly by making it easier to machine the bore of the hydraulicactuator, and by reducing the amount of waste or scrap material.

A further object of the present invention is to simplify the assemblingof the combined power unit and hydraulic actuator.

Other objects and advantages will become apparent during the course ofthe following description, reference being had therein to theaccompanying drawings, in which:

Figure l is a vertical section taken through a combined power unit andhydraulic actuator embodying my invention, the remaining elements of anillustrative pressure transmitting system being shown diagrammatically;and

Figure 2 is a vertical section taken through a second embodiment of myinvention.

Referring to Figure 1 the structure with which I am primarily concernedis the combination of the differential air pressure power cylinderindicated generally at [2 and the hydraulic actuator indicated generallyat It, said hydraulic actuator being operable by the power unit I2. Thecomplete system, which may be used to control the application of brakesor the like, includes a conventional master cylinder IS, a plurality ofconventional wheel cylinders IS, a conduit 20 connecting master cylinderIt to a port 22 provided in the combination power and hydraulic unit,and conduits 24 connecting the wheel cylinders to a port 26 a1soprovided in the combination power and hydraulic unit.

Pressure developed in the manually operated master cylinder it acts onpiston 28 to develop a force acting through rod 30 on piston 32, whichis reciprocable in the bore 34 of hydraulic actuator 14. The pressuredeveloped in the master cylinder It also acts against avalve-operatingpiston 36 which is connected to avalve-seatproviding-member 38. A valve member 4!] is adapted tocooperate with valve seat 38 to control the opening 42 provided in thecenter of said valve seat. In the released position of the system, valvemember 40 is spaced from its seat and aperture 32 therefor permitscommunication between chamber i4 and chamber 46. Because chamber to isconnected by means of conduit 48 with a suitable source or" vacuum, suchas the usual intake manifold, while chamber 44 is connected by means ofconduit 50 with chamber 52 of the power cylinder, which in turn isconnected by passage 53 with chamber 54 of the power cylinder, the rearsurfaces of tandem pistons (or pressure responsive movable members) 56and 53 are normally subJected to vacuum. Chambers (iii and 62, which arein front of the respective pistons 56 and 58, are connected by means ofconduit 6G to the vacuum source. Therefore, when the valve members 38and 4B are in the relative positions shown, vacuum is present on bothsides of both power pistons and spring 66 holds the tandem pistoncombination in the leftward position, as shown, the power pistons beinginterconnected by means of th tube 68. A sealed partition it preventscommunication between chambers 54 and 60 of the power cylinder.

When the pressure acting against piston 36, tending to move the sametoward the left, is sufficient to compress spring 72, valve seat 38contacts valve element to, thereby cutting off communication between thevacuum source, on the one hand, and chambers 52 and 54 of the powercylinder, on the other hand. Further movement of piston 35 towards theleft lifts valve members i l and it from their respective seats, therebypermitting air to flow from chamber 18 into chamber 44 and thence tochambers 52 and 54 of the power cylinder, developing a difierential overthe power cylinder pistons to move the same toward the right. The forceexerted by the power cylinder pistons through rod 30 urges piston 32 inhydraulic actuator i l on its pressure stroke, the total output of thehydraulic actuator being developed by the combined efiort of the powercylinder pistons and of the manually created pressure acting againstpiston 28.

A fast application valvecorresponding to that disclosed in 'I. H. Thomasapplication Serial No. 623,832, filed October 22, 1945, now abandoned,may be used to speed the change of pressure in power cylinder chamber54. This valve includes poppet GI and diaphragm 63 connected thereto.The chamber at the right of the diaphragm is connected by means ofconduit 65 with chamber 44 of the control valve, and the chamber at theleft of the diaphragm is connected by means of passage 67 with chamber54 of the power cylinder. Operation of the fast application valve is 3fully explained in the Thomas application above referred to.

In the released position of piston 32, communication is permittedbetween the bore 34 of actuator I4 and the hydraulic reservoir 80, fluidbeing allowed to flow past ball check valve 82, and through passage 84to the rear of piston 32, whence it communicates through opening 88 withthe reservoir. During the pressure stroke of the power pistons 56 and58, the ball valve 82 cuts off the passage 84 because of the removal ofpressure exerted on forked member 88 by washer 90, which in releasedposition causes the forward extension 92 of said forked member to holdthe ball valve away from its seat.

The present invention is primarily concerned with the construction ofthe front or right end of power cylinder I2 and the hydraulic actuatorI4 which is supported thereon. In general, power cylinder I2 comprises acylindrical shell 94, to which is secured by suitable means, such as aplurality of bolts 98, an end plate 98. In the illustrated powercylinder, because it is designed to use a tandem piston construction, asecond shell I is provided, separated from the shell 94 by theaforementioned partition 10. At the rear of shell I00 a suitable endplate I02 is provided, which supports the structure of the controlvalve.

The shells B4 and I00 may b conveniently formed by a deep drawingprocess wherein the wall portion is gradually forced outwardly until thecylindrical shape is assumed. End plate I02, partition 10, and end plate98 are all formed by casting, because of the relatively intricate shapeof these parts.

The casting 98 which provides the front end plate of the power cylinderhas formed integral therewith the reservoir casing 90. Also integralwith the end plate 98 is an outwardly extending sleeve or hollow bossI04 which is internally threaded as shown at I08. Screwed into sleeveI04 is a tubular member I08 which may be simply a piece of conventionaltubing provided with suitable externally threaded portions, andinternally machined to obtain the proper wall finish for the hydraulicbore 34.

Th inner end I I0 of tube I08 is suitably guided in casting 98, and theopening 86 is formed in the'wall of the tube.

The power piston 58 is connected by means of the cross-pin I I2 to therod 30, the front end of said rod being connected by means of across-pin II4 with the piston 32. The rod 80 extends through an openingII6 provided in a closure member or plug I I8 which is inserted in anopening I20 provided through the center of casting 98. Suitable sealsI22 and I24 and a gasket I25 are provided to prevent communicationbetween chamber 62 of the power cylinder and chamber I28 at the rear ofthe hydraulic actuator.

The tube I08, after it has been screwed into the threaded openingprovided in sleeve I04, is secured in position by means of a lock nutI28. A suitable seal I30 is required to prevent escape of liquid fromthe reservoir 80 along the outer surface of the tube I08, and the usualseal I 32 is provided to prevent communication between chamber I34 ofthe hydraulic actuator and chamber I26 thereof, except through passage84 in piston 32.

Secured to the forward end of tube I08, as by the illustrated threadedconnection, is a fitting I36, which contains the port 26, into which theend of conduit 24 may be inserted, the fitting 4 I36 also containing ableed opening I38 normally closed by plug I40.

The combination of a power cylinder end plate having an integral sleevewith a tubular member secured in said sleeve and machined to form acylinder bore has certain important advantages over power operatedhydraulic actuators heretofore used: (1) the walls of tube I08 are lesslikely to have objectionable porosity than the Walls of a cast cylinder;(2) the tubular member I08 is easier to handle during machining of thehydraulic bore than a casting would be; and (3) if, for any reason, thebore of the hydraulic actuator proves to be unfit, only the tube need bescrapped and the rest of the parts are not affected. The significance ofthe listed advantages is due to the fact that the critical part of acombination unit of this type is the bore in which the hydraulic pistonoperates. The requirements as to the other parts of the structure arenot so critical and do not require such careful handling and inspection.

An additional advantage of the present invention lies in the ease withwhich the structure may be assembled. Heretofore it would have beenextremely dimcult to assemble a hydraulic piston having a directmechanical connection with the operating rod, such as that provided bypin II4. Such a direct mechanical connection between the power pistonand the hydraulic piston is advantageous because the power cylinderreturn spring retracts the hydraulic piston, and there is no need for anadditional return spring in the hydraulic actuator. With the presentconstruction, after the power cylinder has been assembled, and the endplate 98 secured thereto, the power piston assembly may be drawn towardthe right by applying suitable pressure thereto, thus causing the end ofrod 30 to protrude beyond the casting 98. It is relatively simple toconnect piston 32 to the protruding end of rod 30 by means of pin II4,and then slide tube I08 over piston 32 and screw the tube into positionin member 90.

Figure 2 illustrates the application of the principles of my inventionto a smaller unit having a single-piston power cylinder. In thisconstruction, the power cylinder may consist primarily of a cup-shapedstamped shell I42 which contains a power piston (or pressure responsivemovable wall) I44, and to the front end of which is secured a castingI48. The casting I48 is provided with a forwardly extending sleeve orhollow boss I48 which is internally threaded as shown at I50 to receivethe externally threaded tubular member I52. Rod I54 is provided with athreaded portion I56 and may thus be clamped by means of nut I58 topower piston I44. At its forward end rod I54 is secured by means of pinI58 to piston I60, which is reciprocable in the bore I82 provided intubular member I52.

Because port I64 is connected directly to the operator operated mastercylinder, there is no need for a reservoir in this construction. PortIE4 is connected through chamber I66 and passage I68 with the chamberI10, in which is located valve operating piston I12. Chamber I14 of thepower cylinder is in constant communication with the vacuum sourcethrough a suitable port (not shown), and, in released position of theunit, chamber I18 of the power cylinder is also connected to the vacuumsource through conduit I and port I82 of the valve. Movement of pistonI12 under the influence of pressure developed in the operator operatedmaster cylinder first cuts oif chamber I18 from the vacuum source andsubsequently brings it into communication with the air which entersthrough chamber I85, thereby causing the power piston to travel towardthe right and move piston I68 on the pressure stroke. The manuallydeveloped pressure present in chamber I55 acts against the rear ofpiston its to assist the power piston in developing brake applyingeffort.

As in the embodiment shown in Figure l, a suitable fltting I 85 issecured to tube 452 at the outer end thereof, a lock nut 88 is used tosecure tube i52 in position, and a suitable plug or closure member Hillis used to close the centrally located opening in end plate hi5, exceptfor the hole I92 through which the rod lEd extends.

It will be apparent that the casting Hi6 not only provides an end platefor the power cylinder and a sleeve to receive the tubular member I52,but also furnishes part of the casing of the control valve, the castingHid bEiIlg secured thereto to complete the valve housing. In order toprovide a bore for valve operating piston ['52, a sleeve I96 may besecured in place in casting E56, as shown.

Although particular embodiments of my invention have been described, itwill be understood by those skilled in the art that the object of theinvention may be attained by the use of constructions different incertain respects from those disclosed without departing from theunderlying principles of the invention. I therefore desire by thefollowing claims to include within the scope of my invention all suchvariations and modifications by which substantially the results of myinvention may be obtained through the use of substantially the same orequivalent means.

I claim:

l. A combined differential air pressure power unit and hydraulicactuator operated thereby comprising a cup-shaped shell for said powerunit, a power piston reciprocable in said shell, an end plate secured toone end of said shell having an opening through the center thereof andhaving an integral hollow internally threaded boss concentric with saidopening and extending outwardly from the end plate, an externallythreaded tube secured in said boss and providing a hydraulic mastercylinder bore, a housing member secured to said end plate eccentricallylocated with respect to the end plate center and forming together withthe end plate the casing of a control valve, a piston reciprocable inthe hydraulic master cylinder bore, a rod secured to the power piston, across-pin connecting said rod to the hydraulic piston, a closure memberclosing the centrally located opening through the end plate except for ahole which accommodates the aforementioned rod, a lock-nut screwed ontosaid threaded tube and resting against the outer end of the hollow bossto retain the threaded tube in position, and a fitting secured to theouter end of the tubular member and adapted to receive the end of aliquid-carrying conduit.

2. A combined difierential air pressure power unit and hydraulicactuator operated thereby comprising a cylindrical shell for said powerunit, a pressure responsive movable wall reciprocable in said shell, anend plate secured to one end of said shell having an integral internallythreaded sleeve extending outwardly therefrom, a control valve casing onsaid end plate and offset to one side of said sleeve, an externallythreaded tube secured in said sleeve and providing a hydraulic mastercylinder bore, a piston slidably received in said bore, means connectingsaid piston to the aforementioned pressure responsive movable wall,

a lock-nut screwed onto said tubular member and resting against thehollow end of the sleeve to retain the tubular member in position, and ableed port provided in said tube and fixed in a predetermined positionby means of the cooperative relationship between the lock-nut and theconnection between the tube and the end plate.

3. A combined differential air pressure power unit and hydraulicactuator operated thereby comprising a cylindrical shell for said powerunit, a pressure responsive movable wall reciprocable in said shell, anend plate secured to one end of said shell having an integral internallythreaded sleeve extending outwardly therefrom, a control valve casing onsaid end plate and offset to one side from said sleeve, an externallythreaded tube secured in said sleeve and providin a hydraulic mastercylinder bore, a piston slidably received in said bore, and meansconnecting said piston to the aforementioned pressure responsive movablewall.

4. A combined differential air pressure power unit and hydraulicactuator operated I thereby comp-rising a cylindrical shell for saidpower unit, a pressure responsive movable wall reciprocable in saidshell, an end plate mounted on one end of said shell having an integralinternally threaded sleeve extending outwardly therefrom, a controlvalve casing integral with said end plate and offset to one side of saidsleeve, a plurality of bolts extending longitudinally from the end plateto the rear of the power unit to retain said end plate in tightengagement with the front of the shell, an externally threaded tubularmember secured in the end plate sleeve and providing a hy draulic mastercylinder bore, a piston slidably received in said bore, means connectingsaid piston to the aforementioned pressure responsive 'movable wall, anda lock nut screwed onto said tubular member and engaging the outer endof the end plate sleeve to retain the tubular member in position.

5. A combined differential air pressure power unit and hydraulicactuator operated thereby comprising a cylindrical shell for said powerunit, a pressure responsive movable wall reciprocable in said shell, anend plate mounted on one end of said shell having an integral internallythreaded sleeve extending outwardly therefrom, a control valve housingon said end plate at a location offset to one side of said sleeve, afirst bleed outlet in said housing, a plurality of boltsextendinglongitudinally from the end plate to the rear of the power unitto retain said end plate in tight engagement with the front of the shelland to locate said bleed port in a predetermined position, an externallythreaded tubular member secured in the end plate sleeve and providing ahydraulic master cylinder bore, a piston slidably received in said bore,means connecting said piston to the aforementioned pressure responsivemovable wall, a lock nut screwed onto said tubular member and engagingthe outer end of the end plate sleeve to retain the tubular member inposition, a second bleed outlet for said bore and securely located onthe same side of said bore as said first bleed outlet by means of saidlock-nut and the connection between said sleeve and said externallythreaded tubular member, and a fitting secured to the outer end of thetubular member and adapted to receive the end of the liquid-carryingconduit.

6. A combined differential air pressure power unit and hydraulicactuator operated thereby comprising a cup-shaped shell for said powerunit, a power piston re'ciprocable in said shell, an

end plate secured to one end of said shell having an openingtherethrough and having an integral hollow internally threaded bossconcentric with said opening and extending outwardly from the end plate,an externally threaded tube secured in said boss and providing ahydraulic master cylinder bore, a housing member secured to said endplate eccentrically located with respect to the end plate center andforming together with the end plate the casing of a control valve, apiston reciprocable in the hydraulic master cylinder bore, a rod securedto the power piston, a crosspin connecting said rod to the hydraulicpiston, a closure member closing the opening through the end plateexcept for a hole which accommodates the aforementioned rod, a lock-nutscrewed onto said threaded tube and resting against the outer end of thehollow boss to retain the threaded tube in position, and a fittingsecured to the outer end of the tubular member and adapted to receivethe end of a liquid-carrying conduit.

7. A combined differential air pressure power unit and hydraulicactuator operated thereby comprising a cup-shaped shell for said powerunit, a power piston reciprocable in said shell, an end plate secured toone end of said shell having an opening therethrough and having anintegral hollow internally threaded boss concentric with said openingand extending outwardly from the end plate, an externally threaded tubesecured in said boss and providing a hydraulic master cylinder bore, ahousing member secured to said end plate eccentrically located withrespect to the end plate center and forming together with the end platethe casing of a control valve, a piston reciprocable in the hydraulicmaster cylinder bore, a rod secured to the power piston, a closuremember closing the opening through the end plate except for a hole whichaccommodates the aforementioned rod, a lock-nut screwed onto saidthreaded tube and resting against the outer end of the hollow boss toretain the threaded tube in position, and a fitting secured to the outerend of the tubular member and adapted to receive the end of aliquid-carrying conduit.

8. A combined difierential air pressure power unit and hydraulicactuator operated thereby comprising a cup shaped shell for said powerunit, a power piston reciprocable in said shell, an end plate secured toone end of said shell having an opening therethrough and having anintegral hollow internally threaded boss concentric with said openingand extending outwardly from the end plate, an externally threaded tubesecured in said boss and providing a hydraulic master cylinder bore, ahousing member secured to said end plate eccentrically located withrespect to the end plate center and forming together with the end platethe casing of a control valve, a piston reciprocable in the hydraulicmaster cylinder bore, a rod secured to the power piston, a closuremember closing the opening through the end plate except for a hole whichaccommodates the aforementioned rod, and a lock-nut screwed onto saidthreaded tube and resting against the outer end of the hollow boss toretain the threaded tube in position.

9. A combined differential air pressure power unit and hydraulicactuator operated thereby comprising a cup-shaped shell for said powerunit, a power piston reciprocable in said shell, an end plate secured toone end of said shell having an opening therethrough and having anintegral hollow internally threaded section concentric with saidopening, an externally threaded tube secured in said section andproviding a hydraulic master cylinder bore, a housing member on said endplate eccentrically located with respect to said bore and formingtogether with the end plate the casing of a control valve, a pistonreciprocable in the hydraulic master cylinder bore, a rod secured to thepower piston, a closure member closing the opening through the end plateexcept for a hole which accommodates the aforementioned rod, and alock-nut screwed onto said threaded tube and resting against the outerend of the hollow boss to retain the threaded tube in position.

EVUE J. RINGER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,781,869 Bragg Nov. 18, 19301,987,651 Wiegand Jan. 15, 1935 2,078,209 Sanford Apr. 20, 19372,241,374 Alfieri May 13, 1941 2,251,952 Price Aug. 12, 1941 2,260,492Stelzer Oct. 28, 1941 2,399,719 Bergh May 7, 1946

